I've got a beat up old RB Graflex Series D 4x5 that I tune up and make it a user camera. Two questions at the moment:

* what does a lens board look like for one of these? Mine has neither lens nor board. Looking at the place the board would go, there's a spring at the top, so I suspect a plain flat board of the right size & thickness would work. What are the correct dimensions for a lens board? Is the lens board beveled, does it have a notch or step in the sides to act as a light trap?

* shutter curtain clearance/drag: the shutter curtain drags on the rotating back. How much clearance should there be between the curtain and the back? It seems like there should be at least a little visible clearance, but the curtain, even under tension, touches the back all around. I've taken the back apart now, and discovered the felt between the rotating and stable parts was much damaged (moths, I think) and I'll replace it, but it still looks like the back will be too close to the curtain. Thoughts?